PCI: hv: Use pci_function_description[0] in struct definitions

BugLink: http://bugs.launchpad.net/bugs/1650059

The 2 structs can use a zero-length array here, because dynamic memory of
the correct size is allocated in hv_pci_devices_present() and we don't need
this extra element.

No functional change.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: KY Srinivasan <kys@microsoft.com>
CC: Jake Oshins <jakeo@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
(cherry picked from commit 7d0f8eec)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/pci/host/pci-hyperv.c

@@ -259,7 +259,7 @@ struct pci_bus_d0_entry {
 struct pci_bus_relations {
 	struct pci_incoming_message incoming;
 	u32 device_count;
-	struct pci_function_description func[1];
+	struct pci_function_description func[0];
 } __packed;
 
 struct pci_q_res_req_response {
@@ -394,7 +394,7 @@ struct hv_dr_work {
 struct hv_dr_state {
 	struct list_head list_entry;
 	u32 device_count;
-	struct pci_function_description func[1];
+	struct pci_function_description func[0];
 };
 
 enum hv_pcichild_state {